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Abstract:

A method implemented by a middlebox comprising registering a customer
premises equipment (CPE) in the middlebox, wherein the CPE is coupled to
the middlebox via an electrical line, and facilitating registration of
the CPE in a central office (CO) equipment coupled to the middlebox.

Claims:

1. A method implemented by a middlebox comprising: registering a customer
premises equipment (CPE) in the middlebox, wherein the CPE is coupled to
the middlebox via an electrical line; and facilitating registration of
the CPE in a central office (CO) equipment coupled to the middlebox.

2. The method of claim 1, wherein registering the CPE in the middlebox
comprises: transmitting a first discovery message to a plurality of CPEs
including the CPE; receiving a first register request message from the
CPE, wherein the first register request message is generated based on the
first discovery message; assigning a physical layer identifier (PHY ID)
to the CPE based on the first register request message; and transmitting
a first register message comprising the PHY ID to the CPE.

3. The method of claim 2, wherein facilitating registration of the CPE in
the CO equipment comprises: receiving a second discovery message from the
CO equipment; converting the second discovery message to a converted
discovery message; and transmitting the converted discovery message to
the plurality of CPEs;

4. The method of claim 3, wherein facilitating registration of the CPE in
the CO equipment further comprises: relaying a second register request
message from the CPE to the CO equipment, wherein the second register
request message is generated based on the second discovery message;
relaying a second register message from the CO equipment to the CPE,
wherein the second register message comprises a media access control
layer identifier (MAC ID) for the CPE equipment; and relaying a register
acknowledge message from the CPE to the CO equipment, wherein the
register acknowledge message is generated in response to the second
register message.

5. The method of claim 4, further comprising storing the PHY ID and the
MAC ID during or after relaying the second register message.

6. The method of claim 4, wherein the CO equipment is coupled to the
middlebox via an optical line, and wherein the first discovery message
comprises an upstream channel descriptor (UCD) and an upstream media
access plan (MAP).

7. An apparatus comprising: a processor configured to: register a
customer premises equipment (CPE) remotely coupled to the apparatus via
an electrical line; and facilitate registration of the CPE in a central
office (CO) equipment coupled to the apparatus.

8. The apparatus of claim 7, further comprising: at least one transmitter
coupled to the processor; and at least one receiver coupled to the
processor, wherein registering the CPE comprises: the processor
instructing the at least one transmitter to transmit a first discovery
message to a plurality of CPEs including the CPE via electrical lines;
the processor instructing the at least one receiver to receive a first
register request message from the CPE, wherein the first register request
message is generated based on the first discovery message; assigning a
physical layer identifier (PHY ID) to the CPE based on the first register
request message; and the processor instructing the at least one
transmitter to transmit a first register message comprising the PHY ID to
the CPE.

9. The apparatus of claim 8, wherein facilitating registration of the CPE
in the CO equipment comprises: the processor instructing the at least one
receiver to receive a second discovery message from the CO equipment via
an optical line; converting the second discovery message to a converted
discovery message; and the processor instructing the at least one
transmitter to transmit the converted discovery message to the plurality
of CPEs.

10. The apparatus of claim 9, wherein facilitating registration of the
CPE in the CO equipment further comprises: relaying a second register
request message from the CPE to the CO equipment, wherein the second
register request message is generated based on the second discovery
message; relaying a second register message from the CO equipment to the
CPE, wherein the second register message comprises a media access control
layer identifier (MAC ID) for the CPE equipment; and relaying a register
acknowledge message from the CPE to the CO equipment, wherein the
register acknowledge message is generated in response to the second
register message.

11. The apparatus of claim 10, further comprising a memory coupled to the
processor and configured to store the PHY ID and the MAC ID.

12. The apparatus of claim 10, wherein the MAC ID is a logical link
identifier (LLID), the CPEs are coax network units (CNUs), and the CO
equipment is an optical line terminal (OLT).

13. The apparatus of claim 10, wherein the MAC ID is a destination
address (DA), the CPEs are at least one of cable modems (CMs) and set-top
boxes (STBs), and the CO equipment is a cable modem termination system
(CMTS).

14. A method comprising: receiving a first discovery message from a
middlebox coupled to a customer premises equipment (CPE) via an
electrical line; transmitting a first register request message to the
middlebox in response to the first discovery message; receiving a first
register message from the middlebox, wherein the first register message
comprises a physical layer identifier (PHY ID) for the CPE; and receiving
a second discovery message from the middlebox, wherein the second
discovery message comprises an identifier (ID) for a central office (CO)
equipment coupled to the middlebox.

15. The method of claim 14, further comprising: transmitting a second
register request message to the middlebox in response to the second
discovery message; and receiving a second register message from the
middlebox, wherein the second register message comprises a media access
control layer identifier (MAC ID) for the CPE.

16. The method of claim 15, wherein the CO equipment is remotely coupled
to the middlebox via an optical line.

17. The method of claim 15, wherein the MAC ID is either a logical link
identifier (LLID) or a destination address (DA).

18. The method of claim 15, further comprising transmitting a register
acknowledge message to the middlebox in response to the second register
message.

19. The method of claim 15, further comprising exchanging messages
between the CPE and the middlebox to negotiate one or more physical layer
parameters.

20. The method of claim 15, wherein the PHY ID is assigned by the
middlebox, and wherein the MAC ID is assigned by the CO equipment, and
wherein both the PHY ID and the MAC ID are stored in the middlebox.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to U.S. Provisional Patent
Application No. 61/607,734 filed Mar. 7, 2012 by Liming Fang et al. and
entitled "Method and Apparatus of extending EPON MPCP to run on Ethernet
PON over Coax Network (EPoC)", which is incorporated herein by reference
as if reproduced in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

[0003] Not applicable.

BACKGROUND

[0004] A passive optical network (PON) is a system for providing network
access over "the last mile." In a downstream direction, the PON may be a
point-to-multi-point (P2MP) network comprising an optical line terminal
(OLT) at a central office, an optical distribution network (ODN), and a
plurality of optical network units (ONUs) at customer premises. Ethernet
passive optical network (EPON) is a PON standard developed by the
Institute of Electrical and Electronics Engineers (IEEE) and specified in
IEEE 802.3ah, which is incorporated herein by reference as if reproduced
in its entirety. EPON may provide a simple and flexible way of using
optical fiber for broadband service in the last mile.

[0005] In EPON, an optical fiber may be used for both upstream and
downstream transmissions with different wavelengths. The optical line
terminal (OLT) may implement an EPON media access control (MAC) layer for
transmission of Ethernet frames. A multi-point control protocol (MPCP)
may perform various services such as bandwidth assignment, bandwidth
polling, auto-discovery, and ranging. Ethernet frames may be broadcasted
downstream based on a logical link identifier (LLID) embedded in a
preamble of each frame. On the other hand, upstream bandwidth may be
assigned based on the exchange of Gate and Report messages between
messages between an OLT and an ONU.

[0006] Recently, hybrid access networks employing both EPON and other
network types have attracted growing attention. For example, Ethernet
over Coax (EoC) may be a generic name used to describe all technologies
that transmit Ethernet frames over a unified optical-coaxial (coax)
network. Examples of EoC technologies may include EPON over coax (EPoC),
data over cable service interface specification (DOCSIS), multimedia over
coax alliance (MoCA), G.hn (a common name for a home network technology
family of standards developed under the International Telecommunication
Union (ITU) and promoted by the HomeGrid Forum), home phoneline
networking alliance (HPNA), and home plug audio/visual (A/V). EoC
technologies may have been adapted to run outdoor coax access from an ONU
to an EoC head end with connected customer premises equipment (CPEs)
located in subscriber homes.

[0007] There is a rising demand to use EPON as an access system to
interconnect with multiple coax cables to terminate coax network units
(CNUs) located in a subscriber's home with an EPoC architecture. In an
EPoC system, as a physical (PHY) layer in the optical network portion may
be relatively cleaner than a physical layer in the coax network portion,
one may need to establish channel communication between CNUs and OLT
before transmission of data. Some traditional discovery and registration
approaches may use EPON MPCP for registration of coaxial line terminals
(CLTs). However, traditional MPCP may not be used for the coax network
portion. Thus, it is desirable to extend the EPON MPCP to the coax
portion of an EPoC network, where noises may be higher.

SUMMARY

[0008] In one embodiment, the disclosure includes a method implemented by
a middlebox comprising registering a customer premises equipment (CPE) in
the middlebox, wherein the CPE is coupled to the middlebox via an
electrical line, and facilitating registration of the CPE in a central
office (CO) equipment coupled to the middlebox.

[0009] In another embodiment, the disclosure includes an apparatus
comprising a processor configured to register a customer premises
equipment (CPE) remotely coupled to the apparatus via an electrical line,
and facilitate registration of the CPE in a central office (CO) equipment
coupled to the apparatus.

[0010] In yet another embodiment, the disclosure includes a method
comprising receiving a first discovery message from a middlebox coupled
to a customer premises equipment (CPE) via an electrical line,
transmitting a first register request message to the middlebox in
response to the first discovery message, receiving a first register
message from the middlebox, wherein the first register message comprises
a physical layer identifier (PHY ID) for the CPE; and receiving a second
discovery message from the middlebox, wherein the second discovery
message comprises an identifier (ID) for a central office (CO) equipment
coupled to the middlebox.

[0011] These and other features will be more clearly understood from the
following detailed description taken in conjunction with the accompanying
drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] For a more complete understanding of this disclosure, reference is
now made to the following brief description, taken in connection with the
accompanying drawings and detailed description, wherein like reference
numerals represent like parts.

[0013] FIG. 1 illustrates an embodiment of an EPoC network.

[0014] FIG. 2 illustrates an embodiment of a DOCSIS network.

[0015] FIG. 3 illustrates an embodiment of a hybrid access network.

[0016]FIG. 4 illustrates an embodiment of part of a layer architecture in
a hybrid access network.

[0017] FIG. 5 illustrates an embodiment of a registration protocol.

[0018] FIGS. 6A and 6B illustrate an embodiment of a registration method.

[0020] It should be understood at the outset that, although an
illustrative implementation of one or more embodiments are provided
below, the disclosed systems and/or methods may be implemented using any
number of techniques, whether currently known or in existence. The
disclosure should in no way be limited to the illustrative
implementations, drawings, and techniques illustrated below, including
the exemplary designs and implementations illustrated and described
herein, but may be modified within the scope of the appended claims along
with their full scope of equivalents.

[0021] Based on needs at any time (in other words, on demand), a customer
may switch a CNU off and on as desired. The non-contention based design
of EPON as well as EPoC MAC layer may be such that ONUs/CNUs do not
transmit data upstream until they have been allocated a timeslot through
a GATE message. Hence, after a CNU is switched on, it may stay in an idle
state until and unless an OLT assigns it a timeslot, during which it can
send data upstream to the OLT. To solve this problem, the EPoC MAC layer
may need to implement an automatic discovery and registration process for
CNUs by the OLT. In an EPoC base system, services may be labeled as
LLIDs. In order to implement end-to-end services, OLT and CNU may need to
establish LLID registration, where the OLT may assign a unique LLID to
each CNU (or to each service within a CNU, in which case the CNU may have
multiple LLIDs) during the registration process.

[0022] In an EPON, the optical PHY may be relatively cleaner (e.g., less
noise signals) than the coax PHY of a coax network. Hence, EPON may not
need to establish PHY channel communication before transmission. However,
coax PHY may be noisier and need to perform channel training and/or
estimation, such as frequency domain equalization (FEQ), ranging, and
sounding, etc., before transmission. The coax PHY negotiation process may
be decoupled from the EPON MAC layer discovery and registration. One of
the goals of this disclosure is to develop a point-to-multipoint coax PHY
auto negotiation mechanism, which may comprise coax PHY discovery and
parameters negotiations. This process may be independent from the EPON
MAC, thus the OLT may have no knowledge of the CNU registration process.
After the coax PHY negotiation is complete, the EPoC MAC registration may
start, and the OLT may discover newly connected CNUs and assign them
LLIDs.

[0023] Disclosed herein are systems, apparatus, and methods for extending
EPON MPCP to a non-optical portion of a hybrid access network, such as an
EPoC or a DOCSIS network. Using an EPoC as an example, to establish a
communication channel between a CNU (coupled to a CLT via an electrical
line) and an OLT (coupled to the CLT via an optical line), the CLT may
register the CNU in itself first, and then facilitate registration of the
CNU in the OLT. Various messages may be exchanged between the three
parties to perform registration, including for example, discovery
messages, register request messages, register messages, register
acknowledge messages, etc. PHY parameters and other tasks may also be
performed. After registering a CNU in an OLT, the OLT may assign a LLID
to the CNU. The CLT may snoop this process, that is, copying the LLID and
storing in a memory in the CLT.

[0024] Refer now to FIG. 1, which illustrates an embodiment of an EPoC
network 100 comprising an optical portion or segment 102 and an
electrical segment 104. The optical segment 102 may essentially be a PON
and the electrical segment 104 may be a coaxial cable network. The
optical segment 102 may comprise an OLT 110 and one or more ONUs 128
coupled to the OLT 110 via an optical distribution network (ODN). The ODN
may comprise an optical line or fiber 114 and an optical splitter 120
that couples the OLT 110 to an ONU 128. Similarly, the electrical segment
104 may comprise one or more CLTs 130, each of which may be coupled to a
plurality of CNUs 150 via an electrical distribution network (EDN). The
EDN may comprise coax cables 134, amplifiers 136 (only one shown as an
example), and cable taps or splitters 140 and 142.

[0025] In the EPoC network 100, each ONU 128 and its corresponding CLT 130
may be fused together into a single box. The ONU-CLT box may act as a
single device, which may reside at the curb or basement of a house or an
apartment building. The ONU-CLT box may form an interface between the
optical and electrical segments 102 and 104. Following convention in the
art, unless otherwise noted, hereinafter a box including an ONU 128 and a
CLT 130 may simply be referred to as a CLT 130 that has ONU
functionalities. It should be understood that the EPoC network 100 may
comprise any number of CLTs 130 and corresponding CNUs 150 for each OLT
110. The components of the EPoC network 100 may be arranged as shown in
FIG. 1 or any other suitable arrangement.

[0026] The optical segment 102 may be a communication network that does
not require any active components to distribute data between the OLT 110
and the CLTs 130. Instead, the optical segment 102 may use the passive
optical components in the ODN to distribute data between the OLT 110 and
the CLT 130. The optical fiber 114 may have any suitable rating, such as
1 or 10 Giga bits per second (Gbps). Examples of suitable protocols that
may be implemented in the optical segment 102 to include asynchronous
transfer mode PON (APON) and the broadband PON (BPON) defined by the ITU
Telecommunication Standardization Sector (ITU-T) G.983 standard, Gigabit
PON (GPON) defined by the ITU-T G.984 standard, the EPON defined by the
IEEE 802.3ah standard, and the wavelength division multiplexing (WDM) PON
(WDM-PON).

[0027] The OLT 110 may be any device configured to communicate with the
CNUs 150 via the CLT 130. The OLT 110 may reside in a local exchange,
which may be a central office (CO). Further, the OLT 110 may couple or
connect the EPoC network 100 to another network 112, which be any type of
network such as an Internet, synchronous optical network (SONET), or
asynchronous transfer mode (ATM) backbone. For example, the OLT 110 may
act as an intermediary between the CLTs 130 and the network 112.
Specifically, the OLT 110 may forward data received from the network 112
to the CLTs 130, and forward data received from the CLTs 130 onto the
network 112. Although the specific configuration of the OLT 110 may vary
depending on the type of optical protocol implemented in the optical
segment 102, in an embodiment, the OLT 110 may comprise an optical
transmitter and an optical receiver. When the network 112 is using a
network protocol that is different from the protocol used in the optical
segment 102, the OLT 110 may comprise a converter that converts the
protocol of the network 112 to the protocol of the optical segment 102.
The OLT converter may also convert the optical segment 102 protocol into
the network 112 protocol.

[0028] The ODN between the OLT 110 and the CLTs 130 may be a data
distribution system that may comprise optical fiber cables, couplers,
splitters, distributors, and/or other equipment. In data transmission,
Ethernet packets from the OLT 110 may pass through a 1×M passive
splitter or a cascade of splitters and reach each of the CLTs 130, where
M may denote a number of CLTs in the EPoC network 100. M may have any
suitable value, such as 4, 8, or 16, and may be decided by an operator
depending on factors like an optical power budget. Thus, packets may be
broadcasted by the OLT 110 and selectively extracted by the CLTs 130. In
an embodiment, the optical fiber cables, couplers, splitters,
distributors, and/or other equipment are passive optical components.
Specifically, the optical fiber cables, couplers, splitters,
distributors, and/or other equipment may be components that do not
require any power to distribute data signals between the OLT 110 and the
CLTs 130. It should be noted that, if needed, the optical fiber cables
may be replaced by any optical transmission media. In some embodiments,
the ODN may comprise one or more passive or active optical amplifiers.
The ODN may extend from the OLT 110 to the CLTs 130 including ONUs in a
branching configuration as shown in FIG. 1, but may be alternatively
configured as determined by a person of ordinary skill in the art.

[0029] The CLTs 130 may be remotely coupled to the OLT 110. In some
embodiments, one or more CLTs may be located within the OLT 110. In the
downstream direction, each CLT 130 may be any device or component
configured to receive downstream data from the OLT 110, process the
downstream data, and transmit the processed downstream data to
corresponding CNUs 150. The CLT 130 may convert the downstream data
appropriately to transfer the data between the optical segment 102 and
the electrical segment 104. Although terms "upstream" and "downstream"
may be used throughout to denote the locations of various network
features relative to the OLT or similar unit, those skilled in the art
will appreciate that the data flow on the network in the embodiments of
the disclosure is bi-directional. Downstream data received by a CLT 130
may be in the form of optical signals, and downstream data transmitted by
a CLT 130 may be in the form of electrical signals that may have a
different logical structure as compared with the optical signals. In some
embodiments, the CLT 130 is transparent to the CNUs 150 and the OLT 110
in the sense that downstream data sent from the OLT 110 to the CNU 150
may be directly addressed to the CNU 150 (e.g. using a LLID or a
destination address), and vice-versa. As such, the CLT 130 intermediates
between network segments, namely an optical segment 102 and an electrical
segment 104 in the example of FIG. 1.

[0030] The electrical segment 104 of the EPoC network 100 may be similar
to any known electrical communication system. For example, the electrical
segment 104 may also be a P2MP network. Downstream data from a CLT 130
may pass through amplifier(s) and a tap or splitter or a cascade of taps
or splitters to reach one or more CNUs 150. In an embodiment, downstream
data transmission from a CLT 130 to CNUs 150 may not be a broadcast;
instead, a media access plan (MAP) may be used to allocate different
sub-carrier groups to different CNUs using orthogonal frequency-division
multiple access. Thus, in some cases, downstream transmissions may be
unicast from the OLT 110 to the CNUs 150.

[0031] The electrical segment 104 may not require any active components to
distribute data between the CLTs 130 and the CNUs 150. Instead, the
electrical segment 104 may use the passive electrical components in the
electrical segment 104 to distribute data between the CLTs 130 and the
CNUs 150. Alternatively, the electrical segment 104 could use some active
components, such as amplifiers 136. Examples of suitable protocols that
may be implemented in the electrical segment 104 include MoCA, G.hn,
HPNA, and Home Plug AN, etc. The EDN between the CLTs 130 and the CNUs
150 may be a data distribution system that comprises electrical cables
(e.g. coaxial cable and twisted wires), couplers, splitters,
distributors, and/or other equipment. In an embodiment, the electrical
cables, couplers, splitters, distributors, and/or other equipment are
passive electrical components. Specifically, the electrical cables,
couplers, splitters, distributors, and/or other equipment may be
components that do not require any power to distribute data signals
between the CLT 130 and the CNU 150. It should be noted that, if needed,
the electrical cables may be replaced by any electrical transmission
media. In some embodiments, the EDN may comprise one or more electrical
amplifiers 136. The EDN may extend from each CLT 130 to its corresponding
CNUs 150 in a branching configuration as shown in FIG. 1, but may be
alternatively configured as determined by a person of ordinary skill in
the art.

[0032] In an embodiment, each CNU 150 may be any device configured to
communicate with the OLT 110, the CLT 130, and any user devices 160.
Specifically, the CNUs 150 may act as an intermediary between the OLT 110
and the user devices 160. For example, each port of the OLT 110 may serve
32, 64, 128, or 256 CNUs, and depending on the number of CNUs present in
the EPoC network 100, a suitable number (e.g., 4, 8, or 16) of CLTs 130
may be deployed per OLT port. An exemplary distance between the OLT 110
and a CLT 130 may be in the range of 10 to 20 kilometers, and an
exemplary distance between a CLT 130 and a CNU 150 may be in the range of
100 to 500 meters. Further, each CNU 130 may serve any suitable number
(e.g., 3 or 4) of subscribers or user devices 160. For instance, the CNUs
150 may forward data received from the OLT 110 to the user devices 160,
and forward data received from the user devices 160 onto the OLT 110.

[0033] Although the specific configuration of the CNUs 150 may vary
depending on the type of network 100, in an embodiment a CNU 150 may
comprise an electrical transmitter configured to send electrical signals
to a CLT 130 and an electrical receiver configured to receive electrical
signals from the CLT 130. Additionally, the CNU 150 may comprise a
converter that converts the electrical signal into electrical signals for
the user devices 160, such as signals in an ATM protocol, and a second
transmitter and/or receiver that may send and/or receive the electrical
signals to the user devices 160. In some embodiments, CNUs 150 and
coaxial network terminals (CNTs) are similar, and thus the terms are used
interchangeably herein. The CNUs 150 may typically be located at end-user
locations, such as the customer premises, but may be located at other
locations as well.

[0034] The user devices 160 may be any devices configured to interface
with a user or subscriber. For example, the user devices 160 may include
desktop computers, laptop computers, tablets, mobile phones, smartphones,
telephones, mobile telephones, residential gateways, televisions, set-top
boxes, and so forth.

[0035] FIG. 2 illustrates an embodiment of a DOCSIS network 200, which may
be structurally similar to the EPoC network 100. The DOCSIS network 200
may comprise a cable modem termination system (CMTS) 210, at least one
hybrid fiber coax (HFC) node 230, any number of cable modems (CMs) 250
and/or set-top box (STB) 252 arranged as shown in FIG. 2. Specifically,
the HFC node 230 may be coupled to the CMTS 210 via an optical fiber 214,
and the CMs 250 and/or STB 252 may be coupled to the HFC node 230 via
electrical cables, one or more amplifiers (e.g., amplifiers 236 and 238),
and at least one splitter 240). In implementation, the CMTS 210 may be
considered equivalent or similar to the OLT 110 in FIG. 1, the HFC node
230 may be considered equivalent or similar to a CLT 130 in FIG. 1, and a
CM 250 or a STB 252 may be considered equivalent or similar to a CNU 150
in FIG. 1. Note that the HFC node 230 may be remotely coupled to the CMTS
210, or sometimes reside in the CMTS 210. The CMTS 210 may sometimes be
equipped with part or all of the functionalities of the HFC node 230. For
example, methods and schemes taught herein (e.g., part of registration
protocols) may be implemented by the CMTS 210 if desired. Instead of
using a LLID, each CM 250, or STB 252, or each service in a CM 250, or
each service in a STB 252, may be identifiable using a destination
address (DA). The DA may be contained in a preamble of an Ethernet frame.
A person of ordinary skill in the art will recognize similarities between
the networks 100 and 200, and that schemes and methods taught by this
disclosure will be applicable to the DOCSIS network 200 (adopting minor
modifications). Accordingly, in the interest of conciseness the DOCSIS
network 200 will not be described as detailed as the EPoC network 100.

[0036] Although not illustrated and discussed exhaustively, it should be
understood that principles of this disclosure may be applicable to any
hybrid access network that employs an optical portion or segment. FIG. 3
illustrates an embodiment of a hybrid access network 300, which may be
structurally similar to the EPoC network 100 or the DOCSIS network 200.
The network 300 may comprise a CO equipment 310, one or more middleboxes
330, and a plurality of CPEs 350 arranged as shown in FIG. 3.
Specifically, the middleboxes 330 may be coupled to the CO equipment 310
via an optical line comprising optical fibers 314 and at least one
splitter 320. The CPEs 350 may be coupled to a middlebox 330 via
electrical lines comprising electrical cables and at least one splitter
340. Note that a middlebox 330 may be remotely coupled to the CO
equipment 310, or sometimes reside in the CO equipment 310. A CPE 350 may
be a plug-and-play device from a user's perspective. Further, each CPE
350 may be identifiable using a MAC layer identifier 453 (in short as MAC
ID) contained in a preamble of an Ethernet frame. This may include some
cases where each service in a CPE 350 is identifiable using a MAC ID.

[0037] In implementation, the OLT 110 in FIG. 1 or the CMTS 210 in FIG. 2
may be considered a specific case of the CO equipment 310, a CLT 130 or a
HFC node 230 may be considered a specific case of the middlebox 330, and
a CNU 150 or a CM 250 or a STB 252 may be considered a specific case of
the CPE 350. Depending on the application or context, a middlebox 330 may
be referred to by various names, including but not limited to: CLT, HFC
node, optical coax converter unit (OCU), coax media converter (CMC),
media converter (MC), and fiber to coax unit (FCU). A person of ordinary
skill in the art will recognize similarities between the networks 100,
200, and 300, and that schemes and methods taught for one specific type
of network will be applicable to a more general network, such as the
hybrid access network 300 (adopting minor modifications as necessary).
Accordingly, in the interest of clarity, in following descriptions
exemplary embodiments of apparatus, systems, schemes, and methods will
mainly direct toward an EPoC network, with the understanding that the
same or similar principles may be applied to any general hybrid access
network.

[0038]FIG. 4 illustrates an embodiment of part of a layer architecture
400 in a hybrid access network (e.g., in the hybrid access network 300).
As shown in FIG. 4, a CO equipment 310 may have a MAC layer 412 and a PHY
layer 414 underneath. A middlebox 330 may have a MAC layer 432, and two
PHY layers 434 and 436 underneath the MAC layer 432. A CPE 350 may have a
MAC layer 452 and a PHY layer 454 underneath. The MAC layers 412, 432,
and 452 may be similar to each other. For example, in an EPoC setting,
the MAC layers 412, 432, and 452 may all be Ethernet MAC layers
processing Ethernet frames. The middlebox 330 serves as an interface
point between an optical segment and an electrical segment of the hybrid
access, thus its PHY layer 434 may interact with the PHY layer 414, while
its PHY layer 436 may interact with the PHY layer 454. In the EPoC
setting, the PHY layers 414 and 434 may be EPON optical PHY layers, and
the PHY layers 436 and 454 may be EPoC coax PHY layers.

[0039] The CO equipment 310 may have an identifier, and so may the CLT
330. A MAC layer identifier 453 (in short as MAC ID) may be used in the
MAC layer 452, and a PHY layer identifier 455 (in short as PHY ID) may be
used in the PHY layer 454. Both the MAC ID 453 and the PHY ID 455 may be
used on different layers to identify the CPE 350. For example, the CO
equipment 310 may assign the MAC ID 453 to the CPE 350, and the middlebox
330 may assign the PHY ID 455 to the CPE 350. Further, the middlebox 330
may store a lookup or mapping table, which comprises both the MAC ID 453
and the PHY ID 455 for multiple CPEs including the CPE 350. In an EPoC
network, the MAC ID 453 may be a LLID of a CNU, while in a DOCSIS
network, the MAC ID 453 may be a DA of a CM or a STB.

[0040] The layer architecture 400 may be considered a convergence layer
architecture. Depending on the implementation, there may be a variety of
layer architectures for a hybrid access network, including but not
limited to, convergence layer, repeater architecture, bridged
architecture, and any combination thereof One with ordinary skill in the
art will recognize that schemes and methods disclosed herein may be
employed to any layer architectures.

[0041] FIG. 5 illustrates an embodiment of a registration protocol 500
implemented in an EPoC network (e.g., the EPoC network 100). The
registration protocol 500 may be a MPCP that allows a CNU 150 to be
registered in both the CLT 130 and the OLT 110. The registration protocol
500 may comprise any number of steps, e.g., 8 steps labeled as 510, 520,
530, 540, 550, 560, 570, and 580 in FIG. 5. Steps 510 to 530 may be
considered a first stage 502 for registration of the CNU 150 in the CLT
130, while steps 540 to 580 may be considered a second stage 504 for
registration of the CNU 150 in the CLT 130. Further, the stage 502 may be
implemented on a physical layer (in short as PHY) to complete coax PHY
discovery and parameter negotiation, while the stage 504 may be
implemented on a media access control layer (in short as MAC) to complete
EPoC MAC discovery and registration.

[0042] After the CNU 150 is powered on and connected to an electrical line
(e.g., a coax cable in the EPoC network), the CNU 150 may begin listening
to the downstream coax channel. In step 510, the CLT 130 may allocate a
coax PHY discovery window or time period by transmitting or sending out a
discovery message to all CNUs coupled to the CLT 130 via electrical
lines. The discovery message may be broadcasted periodically for
discovering newly connected CNUs. The downstream coax channel may
comprise a control channel on reserved and spaced subcarriers or tones.
The reserved tones may be selected from a frequency spectrum of the
downstream channel to carry a downstream media access plan (MAP). The CNU
150 may be aware of the control channel. Specifically, by decoding the
downstream MAP in every orthogonal frequency-division multiplexing (OFDM)
symbol, the CNU 150 may detect or sense when the CLT 130 is performing
step 510, that is, broadcasting discovery messages to all CNUs coupled to
the CLT 130. The discovery message may comprise the downstream MAP, which
contains all LLIDs of CNUs already registered in the OLT 110.
Accordingly, CNUs already registered in the CLT 130 may ignore the
discovery message, while the newly connected CNU 150 may process and
respond to the discovery message.

[0043] A discovery message may comprise various information useful for
communication between the CLT 130 and the CNU 150. In an embodiment, the
discovery message may specify an upstream channel descriptor (UCD), which
informs the CNU 150 which upstream frequencies to transmit on, symbol
rate, modulation profile, and other parameters necessary for
communication. In addition, the discovery message may comprise an
upstream MAP, which may specify allocation of bandwidth to the CNU 150,
that is, using which bandwidth the CNU 150 may respond to the CLT 130.

[0044] In step 520, the CNU 150 may transmit a register request message,
denoted as REGISTER_REQ, to the CLT 130. The REGISTER_REQ may be
transmitted and received on the PHY. In step 530, the CLT 130 may respond
to the REGISTER_REQ with a register, denoted as REGISTER. The register
message may be transmitted from the CLT 130 to the CNU 150 to indicate
completion of registration. Alternatively, the CLT 130 may transmit a
register continue message to the CNU 150 to indicate that further
processes are needed before registration of the CNU 150 can be completed.
Various PHY parameters and/or processes may be negotiated between the CLT
130 and the CNU 150 through the register request and response messages
during steps 520 and 530. Exemplary PHY parameters and processes include,
but are not limited to, ranging, forward error correction, sounding, FEQ,
profile negotiation in terms of channel frequencies, channel numbers,
other parameters or processes, and combinations thereof.

[0045] Since PHY parameter and process negotiations (e.g., ranging) may
sometimes take multiple attempts, the steps 520 and 530 may need to
iterate more than once. Once negotiation is completed, the CLT 130 may
assign a PHY ID to the CNU 150, and transmit a register message
comprising the PHY ID to the CNU 150. The CLT 130 may also store the PHY
ID in its own memory. After receiving the PHY ID, the CNU 150 has
finished PHY registration with the CLT 130. Depending on the
implementation, the CNU 150 may or may not send a register acknowledge
message to the CLT 130 to confirm its registration. After registration, a
coax channel between the CLT 130 and the CNU 150 may be initialized. Note
that in stage 502, the CNU 150 may still lack a LLID it needs to
communicate with the OLT 110.

[0046] In the stage 504, the CLT may facilitate the registration of the
CNU 150 in the OLT 110 by serving as an intermediary. Specifically, in
step 540, the OLT may allocate an optics discovery window by transmitting
a second discovery message to the CLT 130 via an optical line. In
implementation, the second discovery message may be broadcasted
periodically (e.g., as multiple messages having the same or similar
contents) to all CLTs coupled to the OLT 110 via optical lines, including
the CLT 130 shown in FIG. 5. The second discovery message may be
broadcasted for the purpose of registering all newly connected CNUs in
the OLT 110.

[0047] In step 550, the CLT 130 may transform the optics discovery window
to another coax discovery window for the CNU 150. Specifically, the CLT
130 may convert the second discovery message into a converted discovery
message, and then transmit the converted discovery message to the CNU
150.

[0048] In step 560, the CLT 130 may relay a second register request
message (i.e., REGISTER_REQ) from the CNU 150 to the OLT 110.
Specifically, a MAC layer of the CNU 150 may transmit the second register
request message to the CLT 130, which may then forward or relay it to the
OLT 110. Note that relaying or forwarding a message herein may include
cases in which certain processing are applied to the message prior to
relaying. For example, to fit the second register request message for
propagation in an optical line between the OLT 110 and the CLT 130, the
CLT 130 may convert a structure of the second register request message as
necessary. For another example, the CLT 130 may change a time stamp
contained in a message to address potential time differences between the
coax network and the optical network.

[0049] In step 570, the OLT 110 may parse and verify the second register
request message. After verification, the OLT 110 may allocate or assign a
LLID to the CNU 150 by transmitting a second register message (i.e.,
REGISTER) comprising the LLID to the CNU 150 via the CLT 130, which
relays the register message. The LLID may be unique for the CNU 150.
Depending on the implementation, the CNU 150 may have one LLID or each
service in the CNU 150 may have its own LLID. The CNU 150 may store its
assigned LLID(s) to indicate registration of itself in the OLT 110.

[0050] Further, the CLT 130 may snoop the process of CNU registration,
that is, copy the LLID for the CNU 150 from the second register message,
and store the LLID to its own memory. Recall that the CLT 130 may already
have the PHY ID for the CNU 150, thus the CLT 130 may establish
correspondence between the PHY ID and the LLID for the CNU 150. For
example, the CLT 130 may setup a mapping or lookup table to indicate
correspondence from the PHY ID to the LLID, or vice versa. In addition,
for request and allocation of bandwidth, GATE and REPORT messages may be
communicated between the OLT 110 and the CNU 150, and the CLT 130 may
relay the messages.

[0051] In step 580, the CNU 150 may transmit a register acknowledge
message, denoted as REGISTER_ACK, to the OLT 110 via the CLT 130.
REGISTER_ACK may signal that the registration of the CNU 150 in the OLT
130 has been successful. Thus, a channel between the OLT 110 and the CNU
150 via the CLT 130 may be initialized, and data may be communicated. It
can be seen that a MPCP has been effectively extended from an EPON to an
EPoC.

[0052] Table 1 illustrates an embodiment of a LLID lookup table, which may
be stored in a buffer of the CLT 130. The LLID lookup table may comprise
various information, such as PHY IDs of all CNUs coupled to the CLT 130,
LLIDs of all CNUs coupled to the CLT 130, corresponding profiles for each
CNU, and channel parameters such as fast Fourier transform (FFT) sizes
(4092 in Table 1). Note that in Table 1, each CNU may correspond to one
LLID.

[0053] Table 2 illustrates another embodiment of a LLID lookup table,
which may be stored in a buffer of the CLT 130. The LLID lookup table may
comprise various information, such as PHY IDs of all CNUs coupled to the
CLT 130, LLIDs of all CNUs coupled to the CLT 130, corresponding profiles
for each CNU, and channel parameters such as FFT sizes, cyclic prefix
length, etc. Note that in Table 2, each CNU corresponds to multiple
LLIDs, each of which may correspond to one service. Further, a profile
(e.g., profile A) may comprise a modulation order or coding scheme
applied to a specific CNU. Channel Parameters may contain OFDM channel
information, such as symbol duration, FFT size, cyclic prefix (CP)
length, and so on. Also, quality of service (QoS) may be based on each
LLID, and may be extended from the OLT 110, to the CLT 130, and further
to CNUs. QoS may be extended by applying traffic shaping based on each
LLID to guarantee service provider's service level agreement (SLA).

[0054] By applying schemes disclosed herein, EPON MPCP signaling protocol
may be extended to support EPoC network through OLT and CNU registration.
LLID lookup table in the CLT may comprise information designed to map to
the OFDM channel or profile information, so that the OLT can communicate
with the CNUs across optical and electrical lines. Note that EPON ONUs
may coexist with CNU in the EPoC architecture, where MPCP from OLT may
run on either ONU connected to an EPON network, or a CNU connected to an
EPoC network.

[0055] FIGS. 6A and 6B illustrate an embodiment of a registration method
600, which may be implemented by a middlebox (e.g., the middlebox 330) in
a hybrid access network (e.g., the hybrid access network 300). The method
600 may be executed by the middlebox to interact with a CO equipment
coupled to the middlebox via an optical line and a plurality of CPEs
coupled to the middlebox via electrical lines. As a result, one or more
newly connected CPEs may be registered in the middlebox and in the CO
equipment.

[0056] The method 600 may start with step 610, wherein the method 600 may
transmit a first discovery message to a plurality of CPEs including a CPE
which needs to be registered. Recall that discovery messages may be
broadcasted periodically, thus the first discovery message may be any of
the broadcasted messages. In step 620, the method 600 may receive a first
register request message (e.g., on the PHY layer) from the CPE, wherein
the first register request message is generated by the CPE based on the
first discovery message. In step 630, the method 600 may assign a PHY ID
to the CPE based on the first register request message. The PHY ID may
also be stored in the middlebox. In step 640, the method 600 may transmit
a first register message comprising the PHY ID to the CPE. The first
register message may be broadcasted to all CPEs, but other
already-registered CPEs may ignore the message. In step 642, the method
600 may further exchange messages between the CPE and the middlebox to
negotiate one or more physical layer parameters. Steps 610 to 640 or 642
may enable the CPE to be registered in the middlebox.

[0057] Next, in step 650, the method 600 may receive a second discovery
message (e.g., on the MAC layer) from the CO equipment. In step 660, the
method 600 may convert or transform the second discovery message to a
converted discovery message that is suitable for transmission over
electrical lines. In step 670, the method 600 may transmit the converted
discovery message to the plurality of CPEs, wherein the converted
discovery message may or may not comprise a source (e.g., an ID for the
CO equipment and/or ID for the middlebox).

[0058] In step 680, the method 600 may relay a second register request
message (e.g., on MAC layer) from the CPE to the CO equipment, wherein
the second register request message is generated by the CPE based on the
second discovery message. Recall that relaying a message may include
situations in which conversion or processing are performed by the method
600, e.g., to enable the message to travel appropriately in a medium. For
example, the middlebox may change a time stamp contained in a message to
address potential time differences between the coax network and the
optical network. In step 690, the method 600 may relay a second register
message from the CO equipment to the CPE, wherein the second register
message comprises a MAC ID for the CPE equipment. The MAC ID may be
assigned by and transmitted from the CO equipment. In step 692, the
method 600 may store the PHY ID and the MAC ID to establish mapping
between the two IDs. Storing of the MAC ID may occur during or after
relaying the second register message. In step 694, the method 600 may
relay a register acknowledge message from the CPE to the CO equipment,
wherein the register acknowledge message is generated by the CPE in
response to the second register message. Steps 650 to 694 may be executed
by the middlebox to facilitate registration of the CPE in the CO
equipment.

[0059] It should be understood by one with ordinary skill in the art that
modification and variations may be applied to the method 600 within the
scope of this disclosure. For example, storing PHY IDs may occur at any
suitable time, and mapping PHY IDs with MAC IDs may occur at any time,
e.g., after all other steps are completed. In addition, mapping PHY IDs
with MAC IDs may use any suitable data structure. Some steps may be
skipped or changed in execution order if needed.

[0060] The schemes described above may be implemented on a network
component, such as a computer or network component with sufficient
processing power, memory resources, and network throughput capability to
handle the necessary workload placed upon it. FIG. 7 is a schematic
diagram of an embodiment of a network component or node 1500 suitable for
implementing one or more embodiments of the systems and methods disclosed
herein, such as the registration protocol 500 and the registration method
600.

[0061] The network node 1500 includes a processor 1502 that is in
communication with memory devices including secondary storage 1504, read
only memory (ROM) 1506, random access memory (RAM) 1508, input/output
(I/O) devices 1510, and transmitter/receiver 1512. Although illustrated
as a single processor, the processor 1502 is not so limited and may
comprise multiple processors. The processor 1502 may be implemented as
one or more central processor unit (CPU) chips, cores (e.g., a multi-core
processor), field-programmable gate arrays (FPGAs), application specific
integrated circuits (ASICs), and/or digital signal processors (DSPs),
and/or may be part of one or more ASICs. The processor 1502 may be
configured to implement any of the schemes described herein, including
the registration protocol 500 and the registration method 600. The
processor 1502 may be implemented using hardware or a combination of
hardware and software.

[0062] The secondary storage 1504 is typically comprised of one or more
disk drives or tape drives and is used for non-volatile storage of data
and as an over-flow data storage device if the RAM 1508 is not large
enough to hold all working data. The secondary storage 1504 may be used
to store programs that are loaded into the RAM 1508 when such programs
are selected for execution. The ROM 1506 is used to store instructions
and perhaps data that are read during program execution. The ROM 1506 is
a non-volatile memory device that typically has a small memory capacity
relative to the larger memory capacity of the secondary storage 1504. The
RAM 1508 is used to store volatile data and perhaps to store
instructions. Access to both the ROM 1506 and the RAM 1508 is typically
faster than to the secondary storage 1504.

[0063] The transmitter/receiver 1512 may serve as an output and/or input
device of the network node 1500. For example, if the transmitter/receiver
1512 is acting as a transmitter, it may transmit data out of the network
node 1500. If the transmitter/receiver 1512 is acting as a receiver, it
may receive data into the network node 1500. Further, the
transmitter/receiver 1512 may include one or more optical transmitters,
one or more optical receivers, one or more electrical transmitters,
and/or one or more electrical receivers. The transmitter/receiver 1512
may take the form of modems, modem banks, Ethernet cards, universal
serial bus (USB) interface cards, serial interfaces, token ring cards,
fiber distributed data interface (FDDI) cards, and/or other well-known
network devices. The transmitter/receiver 1512 may enable the processor
1502 to communicate with an Internet or one or more intranets. The I/O
devices 1510 may be optional or may be detachable from the rest of the
network node 1500. The I/O devices 1510 may include a video monitor,
liquid crystal display (LCD), touch screen display, or other type of
display. The I/O devices 1510 may also include one or more keyboards,
mice, or track balls, or other well-known input devices.

[0064] It is understood that by programming and/or loading executable
instructions onto the network node 1500, at least one of the processor
1502, the secondary storage 1504, the RAM 1508, and the ROM 1506 are
changed, transforming the network node 1500 in part into a particular
machine or apparatus (e.g., a CO equipment, a middlebox, or a CPE having
the functionality taught by the present disclosure). The executable
instructions may be stored on the secondary storage 1504, the ROM 1506,
and/or the RAM 1508 and loaded into the processor 1502 for execution. It
is fundamental to the electrical engineering and software engineering
arts that functionality that can be implemented by loading executable
software into a computer can be converted to a hardware implementation by
well-known design rules. Decisions between implementing a concept in
software versus hardware typically hinge on considerations of stability
of the design and numbers of units to be produced rather than any issues
involved in translating from the software domain to the hardware domain.
Generally, a design that is still subject to frequent change may be
preferred to be implemented in software, because re-spinning a hardware
implementation is more expensive than re-spinning a software design.
Generally, a design that is stable that will be produced in large volume
may be preferred to be implemented in hardware, for example in an ASIC,
because for large production runs the hardware implementation may be less
expensive than the software implementation. Often a design may be
developed and tested in a software form and later transformed, by
well-known design rules, to an equivalent hardware implementation in an
application specific integrated circuit that hardwires the instructions
of the software. In the same manner, as a machine controlled by a new
ASIC is a particular machine or apparatus, likewise a computer that has
been programmed and/or loaded with executable instructions may be viewed
as a particular machine or apparatus.

[0065] At least one embodiment is disclosed and variations, combinations,
and/or modifications of the embodiment(s) and/or features of the
embodiment(s) made by a person having ordinary skill in the art are
within the scope of the disclosure. Alternative embodiments that result
from combining, integrating, and/or omitting features of the
embodiment(s) are also within the scope of the disclosure. Where
numerical ranges or limitations are expressly stated, such express ranges
or limitations may be understood to include iterative ranges or
limitations of like magnitude falling within the expressly stated ranges
or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.;
greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever
a numerical range with a lower limit, Rl, and an upper limit,
Ru, is disclosed, any number falling within the range is
specifically disclosed. In particular, the following numbers within the
range are specifically disclosed: R=Rl+k*(Ru-Rl), wherein
k is a variable ranging from 1 percent to 100 percent with a 1 percent
increment, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5
percent, . . . , 50 percent, 51 percent, 52 percent, . . . , 95 percent,
96 percent, 97 percent, 98 percent, 99 percent, or 100 percent. Moreover,
any numerical range defined by two R numbers as defined in the above is
also specifically disclosed. The use of the term "about" means +/-10% of
the subsequent number, unless otherwise stated. Use of the term
"optionally" with respect to any element of a claim means that the
element is required, or alternatively, the element is not required, both
alternatives being within the scope of the claim. Use of broader terms
such as comprises, includes, and having may be understood to provide
support for narrower terms such as consisting of, consisting essentially
of, and comprised substantially of Accordingly, the scope of protection
is not limited by the description set out above but is defined by the
claims that follow, that scope including all equivalents of the subject
matter of the claims. Each and every claim is incorporated as further
disclosure into the specification and the claims are embodiment(s) of the
present disclosure. The discussion of a reference in the disclosure is
not an admission that it is prior art, especially any reference that has
a publication date after the priority date of this application. The
disclosure of all patents, patent applications, and publications cited in
the disclosure are hereby incorporated by reference, to the extent that
they provide exemplary, procedural, or other details supplementary to the
disclosure.

[0066] While several embodiments have been provided in the present
disclosure, it may be understood that the disclosed systems and methods
might be embodied in many other specific forms without departing from the
spirit or scope of the present disclosure. The present examples are to be
considered as illustrative and not restrictive, and the intention is not
to be limited to the details given herein. For example, the various
elements or components may be combined or integrated in another system or
certain features may be omitted, or not implemented.

[0067] In addition, techniques, systems, subsystems, and methods described
and illustrated in the various embodiments as discrete or separate may be
combined or integrated with other systems, modules, techniques, or
methods without departing from the scope of the present disclosure. Other
items shown or discussed as coupled or directly coupled or communicating
with each other may be indirectly coupled or communicating through some
interface, device, or intermediate component whether electrically,
mechanically, or otherwise. Other examples of changes, substitutions, and
alterations are ascertainable by one skilled in the art and may be made
without departing from the spirit and scope disclosed herein.